This invention relates to an arrangement for detachable coupling of a trailer equipped with wheels which pivot in the direction of travel to a ball hitch at the rear end of a vehicle and in particular to an arrangement which comprises a coupling receptacle at the forward end of the trailer to receive said ball hitch, a locking member for securing the ball hitch in the coupling receptacle, and members to prevent the trailer pivoting about a vertical axis through the ball hitch.
Heretofore numerous different arrangements have been known for coupling a trailer to a ball hitch of a vehicle so that pivoting of the trailer about a vertical axis through the ball hitch is prevented. One usual solution has been to equip the vehicle with two or more ball hitches and the trailer correspondingly with an equal number of coupling receptacles, as, for example, is described in U.S. Pat. No. 4,076,264. This solution is not only expensive but is also inconvenient in use, since each coupling receptacle is equipped with a separate locking device which must be separately locked and opened. Moreover, this solution does not permit the trailer to pivot about a longitudinal axis in its direction of travel, which would be necessary on uneven roads especially.
This drawback has been eliminated by mounting the coupling receptacles on a common rotating axle in the direction of travel. Such a solution, however, is still more expensive and the locking device of each coupling receptacle must still be separately locked and opened.
An arrangement is known from U.S. Pat. No. 2,475,174 for coupling a trailer equipped with pivoting wheels to a vehicle equipped with a single ball hitch. In this arrangement pivoting of the trailer is prevented by a cable, both ends of which are secured to the bumper of the vehicle on opposite sides, the cable being trained about pulleys on the trailer and locked in place by a separate locking device which prevents movement of the cable and thereby also prevents pivoting of the trailer about a vertical axis passing through the ball hitch. Such an arrangement permits the trailer to pivot about lateral and longitudinal axes through the ball hitch, but detachment of the trailer is extremely inconvenient, complicated, and requires the use of tools.
An object of the present invention is accordingly to provide an arrangement for the detachable coupling of a trailer equipped with pivoting wheels to a ball hitch of a vehicle which prevents pivoting of the trailer about a vertical axis through the ball hitch but which permits pivoting of the trailer about lateral and longitudinal axes through the ball hitch and which arrangement is cheap, reliable in operation and simple to use.